When blocks and attestations arrive, they are SSZ-decoded twice: once
for validation and once for processing. This branch enqueues the decoded
block directly for processing, avoiding the second, slow
deserialization.
* move processing of blocks and attestations to queue
* ...and out from beacon_node
* split attestation processing into attestations and aggregates
* also updates metrics
* clean up logging to better follow the lifetime of gossip: arrival,
validation and processing
* drop attestations and aggregates if there are too many
* try to prioritise blocks and aggregates before single-validator
attestations
* Allow sync manager process blocks one by one.
* Log storeBlock() and updateHead() duration.
* Calculate duration only for blocks added without any error.
* Fix float compilation error.
* Fix duration.
* Fix SyncQueue tests.
Add SeenTable to avoid continuous attempts to dead peers.
Refactor onSecond.
Block backward sync while forward sync is working.
SyncManager now checks responses according corresponding requests + tests.
SyncManager now watching for not progressing local_head_slot and resets SyncQueue.
* Add ability to reset state of sync manager.
Fix bug when sync got stuck on `zero-point` reset.
Fix bug when sync got stuck when some of the workers waiting for failing one.
* Remove debugging comments and imports.
* Remove not used pendingLock.
